A T-cell diagnostic test for cystic echinococcosis based on Antigen B peptides.

L Petrone,G Ippolito,A Corpolongo,D Goletti,V Vanini,M Amicosante,E Pozio,A Teggi,M A Gomez Morales,A Ludovisi

doi:10.1111/pim.12499

Abstract

SummaryCystic echinococcosis (CE) immunodiagnosis is still imperfect. We recently set‐up a whole‐blood test based on the interleukin (IL)‐4 response to the native Antigen B (AgB) of Echinococcus granulosus. However, AgB is encoded by a multigene family coding for five putative subunits. Therefore, the aims of this study were to analyse the IL‐4 response to peptides spanning the immunodominant regions of the five AgB subunits and to evaluate the accuracy of this assay for CE diagnosis. Peptides corresponding to each subunit were combined into five pools. A pool containing all peptides was also used (total pool). IL‐4 evaluated by enzyme‐linked immunosorbent assay was significantly higher in patients with CE compared to those without (NO‐CE subjects) when whole‐blood was stimulated with AgB1 and with the total pool. Moreover, IL‐4 levels in response to the total pool were significantly increased in patients with active cysts. Receiver Operator Curve analysis identified a cut‐off point of 0.59 pg/mL predicting active cysts diagnosis with 71% sensitivity and 82% specificity in serology‐positive CE patients. These data, if confirmed in a larger cohort, offer the opportunity to develop new diagnostic tools for CE based on a standardized source of AgB as the peptides.

Highlights

Cystic echinococcosis (CE) is a widespread chronic zoonosis caused by the parasite Echinococcus granulosus sensu lato
We found significant results in the area under curve for AgB1 (AUC) analysis (AUC, 0.73; 95% confidence interval (CI), 0.59- 0.86, P = .004) (Figure 1B)
We evaluated if the whole-blood test based on the Antigen B (AgB) peptide pools is useful for assessing cyst biological viability

Summary

Introduction

Cystic echinococcosis (CE) is a widespread chronic zoonosis caused by the parasite Echinococcus granulosus sensu lato. The parasite forms cysts mainly in the liver causing severe complications. But current tests present low sensitivity (up to 25% negative results).[6] serology does not allow assessing cyst biological viability, cross-reactivity exists and may remain positive after cure, or negative after reactivation,[7,8] causing the need of long follow-up to establish the biological viability loss of the cyst. Not always cyst stage, evaluated by imaging, coincides with cyst biological viability. This is the case of CE3a cysts, having equal probability of being viable or non-v iable, and of CE4 cysts, as a proportion of

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Discussion

Conclusion